In order to get to the waterfall Urridafoss you follow the signs and take a side road which is well marked and located a little bit to the west of the new Thjorsa bridge on highway 1.
Urridafoss is the largest and most spectacular of all the waterfalls of river Thjorsa. It is also located near the coast. The water flows over a strong rock platform, formed during glacial times (Hreppar Formation). Urridafoss is one of the most voluminous waterfalls in Iceland and the average water flow of Thjorsa at Urriðafoss is 360 m³/sek. Only river Olfusa has greater volume (373 m³/sek). The water at Urridafoss drops 6 meters at the highest point.
Thjorsa is the longest river of the country, 230 km. Its catchment area is the interior desert Sprengisandur, the northern highlands, and it discharges the glaciers Vatnajokull, Tungnafellsjokull and Hofsjokull. The river is the natural boundary of the local municipalities Arnes and Rangarvellir. South of the river’s watershed are already a few sizable dams, and the area constitutes the most exploited hydropower area in Iceland.
During winter the river accumulates large floes of ice downstream creating dams where grows considerably. It is fantastic to visit the canyons of Thjorsa below the waterfall of Urridafoss in the spring, when the river is breaking free from the great ice barriers. Enormous floes of ice break into pieces and fall spectacularly into the river.
Salmon swims upriver to the waterfall, jumps and swims further upstream. It is said that the salmon population of Thjorsa has an exceptionally strong and long tailfin in order to clear the 6 m high waterfall. Trout and eel are also found in the river. It is teeming with life, although it seems to be a harsh environment for life at first sight.
Not far above the new bridge there is an older one. If the hydropower dam of Urridafoss is to be constructed, it will be located not far above the older bridge and a considerable reservoir would be created behind it. At the dam the water would be diverted to the east to the control station located underground, but the water would reappear in the river bed about 3 km further downstream. Iceland’s most voluminous waterfall would almost disappear.
Source: Friends of Urridafoss
Photo Credit: Must See in Iceland